Yes, that's why people suggest that a business plan is a good idea when you're starting a business. As part of the process, you think through what you need to spend on items such as legal costs, initial logo and letterhead and, of course, product development; and on assets like equipment, inventory, etc. There's no magic formula, you just have to make your lists and think it through ...

There's a lot of free information online on this site and bplans.com, including the startup costs calculator free online at www.bplans.com.  Look in the business calculators.

You can also find more details on listing starting costs in my new book, The Plan-As-You-Go Business Plan, which is (at least temporarily) online now and in bookstores beginning August of 2008. Look in Chapter 4, "Flesh and Bones," for specifics on startup costs.